How is “in but few” used in this sentence? [duplicate]

Sentence taken from Tchaikovsky’s textbook of Harmony, page 55 (middle of the page)

“The chord of the sixth and fourth can be effectively employed in but few cases. These are as follows:”

What confuses me is “in but few cases”.

Is this sentence indicating: (1.) “The following” are the effectively employable cases? Or (2.) These are the cases where it cannot be effectively employed?

Locked or would comment. It's an old-fashioned way of saying in only a few cases, so what follows is a list of cases where this chord can be used effectively. In this case you can solve your grammatical problem with a piano!